The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Robert D. Van Der Hilst - One of the best experts on this subject based on the ideXlab platform.
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analysis of ambient Noise Energy distribution and phase velocity bias in ambient Noise tomography with application to se tibet
Geophysical Journal International, 2009Co-Authors: Huajian Yao, Robert D. Van Der HilstAbstract:SUMMARY Green’s functions (GFs) of surface wave propagation between two receivers can be estimated from the cross-correlation of ambient Noise under the assumption of diffuse wavefields or Energy equipartitioning. Interferometric GF reconstruction is generally incomplete, however, because the distribution of Noise sources is neither isotropic nor stationary and the wavefields considered in the cross-correlation are generally non-diffuse. Furthermore, medium complexity can affect the empirical Green’s function (EGF) from the cross-correlation if Noise sources are all far away (i.e. approximately plane-wave sources), which makes the problem non-linear. We analyse the effect of uneven ambient Noise distribution and medium heterogeneity and azimuthal anisotropy on phase velocities measured from EGFs with an asymptotic plane wave (far-field) approximation (which underlies most constructions of phase velocity maps). Phase velocity bias due to uneven Noise distribution can be determined (and corrected) if the Noise Energy distribution and the velocity model are known. We estimate the (normalized) azimuthal distribution of ambient Noise Energy directly from the cross-correlation functions obtained through ambient Noise interferometry. The (smaller, second order) bias due to non-linearity can be reduced iteratively, for instance by using the tomographic model that results from the inversion of uncorrected data. We illustrate our method for Noise Energy estimation, phase velocity bias suppression, and ambient Noise tomography (including azimuthal anisotropy) with data from a seismic array (26 stations) in SE Tibet. We show that the phase velocity bias due to uneven Noise Energy distribution (and medium complexity) in SE Tibet has a small effect (<1 per cent) on the isotropic part phase velocities (for T = 10–30 s) and the azimuthal anisotropy obtained before and after bias correction shows very similar pattern and magnitude.
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Analysis of ambient Noise Energy distribution and phase velocity bias in ambient Noise tomography, with application to SE Tibet
Geophysical Journal International, 2009Co-Authors: Huajian Yao, Robert D. Van Der HilstAbstract:SUMMARY Green’s functions (GFs) of surface wave propagation between two receivers can be estimated from the cross-correlation of ambient Noise under the assumption of diffuse wavefields or Energy equipartitioning. Interferometric GF reconstruction is generally incomplete, however, because the distribution of Noise sources is neither isotropic nor stationary and the wavefields considered in the cross-correlation are generally non-diffuse. Furthermore, medium complexity can affect the empirical Green’s function (EGF) from the cross-correlation if Noise sources are all far away (i.e. approximately plane-wave sources), which makes the problem non-linear. We analyse the effect of uneven ambient Noise distribution and medium heterogeneity and azimuthal anisotropy on phase velocities measured from EGFs with an asymptotic plane wave (far-field) approximation (which underlies most constructions of phase velocity maps). Phase velocity bias due to uneven Noise distribution can be determined (and corrected) if the Noise Energy distribution and the velocity model are known. We estimate the (normalized) azimuthal distribution of ambient Noise Energy directly from the cross-correlation functions obtained through ambient Noise interferometry. The (smaller, second order) bias due to non-linearity can be reduced iteratively, for instance by using the tomographic model that results from the inversion of uncorrected data. We illustrate our method for Noise Energy estimation, phase velocity bias suppression, and ambient Noise tomography (including azimuthal anisotropy) with data from a seismic array (26 stations) in SE Tibet. We show that the phase velocity bias due to uneven Noise Energy distribution (and medium complexity) in SE Tibet has a small effect (
Werner Ebeling - One of the best experts on this subject based on the ideXlab platform.
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Controlling uphill motion of an active Brownian particle driven by shot-Noise Energy pulses
Physical Review E, 2013Co-Authors: Alessandro Fiasconaro, Ewa Gudowska–nowak, Werner EbelingAbstract:Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).We study self-propelled motion of an active Brownian particle moving in a periodic, ratchet-type potential and subject to Energy support distributed in quantized portions according to a Poisson spiking process. The motor features of such a system are examined by analyzing its ability to perform work against additional external load. The control parameter of the system is a mean duration time between subsequent Energy pulses. Our analysis indicates that directionality of the motion depends strongly on the correlation time between events of Energy supply and can be adjusted to maintain optimal functionality of the motor. © 2013 American Physical Society.This work was partially supported by Spanish MICINN through DGICYT Project No. FIS2011-25167, and cofinanced by Fondo Europeo de Desarrollo Regional (FEDER) funds and by the European Science Foundation/EPSD (Exploring Physics of Small Devices) project. E.G.-N. acknowledges Grant No. MPD/2009/6 from the Foundation for Polish Science.Peer Reviewe
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Tuning active Brownian motion with shot-Noise Energy pulses
Journal of Statistical Mechanics: Theory and Experiment, 2009Co-Authors: Alessandro Fiasconaro, Ewa Gudowska-nowak, Werner EbelingAbstract:The main aim of this work is to explore the possibility of modeling the biological Energy support mediated by absorption of ATP (adenosine triphosphate) as an energetic shot Noise. We develop a general model with discrete input of Energy pulses and study shot-Noise-driven ratchets. We consider these ratchets as prototypes of Brownian motors driven by Energy-rich ATP molecules. Our model is a stochastic machine able to acquire Energy from the environment and convert it into kinetic Energy of motion. We present characteristic features and demonstrate the possibility of tuning these motors by adapting the mean frequency of the discrete Energy inputs, which are described as a special shot Noise. In particular, the effect of stochastically driven directionality and uphill flux in systems acquiring Energy from the shot Noise is analyzed. As a possible application we consider the motion of kinesin on a microtubule under a constant load force.
Francis Robicheaux - One of the best experts on this subject based on the ideXlab platform.
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Distribution of laser shot-Noise Energy delivered to a levitated nanoparticle
Physical Review A, 2020Co-Authors: T. Seberson, Francis RobicheauxAbstract:This paper quantifies the rate at which laser shot-Noise Energy is delivered to a nanoparticle for the various scenarios commonly encountered in levitated optomechanics. Although previous articles have the same form and dependencies, the proportionality constants often differ in the literature. This paper resolves these discrepancies. The rate at which Energy is delivered to an optically trapped particle's respective degrees of freedom depends on the radiation pattern of scattered light as well as the direction of laser propagation. For a traveling plane wave with linearly polarized light in the Rayleigh regime, this leads the translational shot-Noise heating rate to be proportional to 1/10 of the total rate in the laser polarization direction, 7/10 in the laser propagation direction, and 2/10 in the direction perpendicular to both. Analytical expressions for the shot-Noise heating rate are provided in the Rayleigh limit as well as numerical calculations for particles in the Mie regime for silica and diamond. For completeness, numerical calculations of the shot-Noise heating for silica Mie particles at the focus of a strongly focused laser beam are calculated for varying numerical aperture and common laser wavelengths. Both numerical calculations show that the Rayleigh expression generally gives an overestimate of the shot-Noise heating especially for larger radii but is still a good approximation even for incident focal fields. The exception to the relative decrease is when a Mie resonance is reached which was found for diamond. Lastly, Rayleigh expressions for the rotational shot-Noise heating for a symmetric toplike particle for linear, elliptically, and unpolarized light are also provided.
Huajian Yao - One of the best experts on this subject based on the ideXlab platform.
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analysis of ambient Noise Energy distribution and phase velocity bias in ambient Noise tomography with application to se tibet
Geophysical Journal International, 2009Co-Authors: Huajian Yao, Robert D. Van Der HilstAbstract:SUMMARY Green’s functions (GFs) of surface wave propagation between two receivers can be estimated from the cross-correlation of ambient Noise under the assumption of diffuse wavefields or Energy equipartitioning. Interferometric GF reconstruction is generally incomplete, however, because the distribution of Noise sources is neither isotropic nor stationary and the wavefields considered in the cross-correlation are generally non-diffuse. Furthermore, medium complexity can affect the empirical Green’s function (EGF) from the cross-correlation if Noise sources are all far away (i.e. approximately plane-wave sources), which makes the problem non-linear. We analyse the effect of uneven ambient Noise distribution and medium heterogeneity and azimuthal anisotropy on phase velocities measured from EGFs with an asymptotic plane wave (far-field) approximation (which underlies most constructions of phase velocity maps). Phase velocity bias due to uneven Noise distribution can be determined (and corrected) if the Noise Energy distribution and the velocity model are known. We estimate the (normalized) azimuthal distribution of ambient Noise Energy directly from the cross-correlation functions obtained through ambient Noise interferometry. The (smaller, second order) bias due to non-linearity can be reduced iteratively, for instance by using the tomographic model that results from the inversion of uncorrected data. We illustrate our method for Noise Energy estimation, phase velocity bias suppression, and ambient Noise tomography (including azimuthal anisotropy) with data from a seismic array (26 stations) in SE Tibet. We show that the phase velocity bias due to uneven Noise Energy distribution (and medium complexity) in SE Tibet has a small effect (<1 per cent) on the isotropic part phase velocities (for T = 10–30 s) and the azimuthal anisotropy obtained before and after bias correction shows very similar pattern and magnitude.
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Analysis of ambient Noise Energy distribution and phase velocity bias in ambient Noise tomography, with application to SE Tibet
Geophysical Journal International, 2009Co-Authors: Huajian Yao, Robert D. Van Der HilstAbstract:SUMMARY Green’s functions (GFs) of surface wave propagation between two receivers can be estimated from the cross-correlation of ambient Noise under the assumption of diffuse wavefields or Energy equipartitioning. Interferometric GF reconstruction is generally incomplete, however, because the distribution of Noise sources is neither isotropic nor stationary and the wavefields considered in the cross-correlation are generally non-diffuse. Furthermore, medium complexity can affect the empirical Green’s function (EGF) from the cross-correlation if Noise sources are all far away (i.e. approximately plane-wave sources), which makes the problem non-linear. We analyse the effect of uneven ambient Noise distribution and medium heterogeneity and azimuthal anisotropy on phase velocities measured from EGFs with an asymptotic plane wave (far-field) approximation (which underlies most constructions of phase velocity maps). Phase velocity bias due to uneven Noise distribution can be determined (and corrected) if the Noise Energy distribution and the velocity model are known. We estimate the (normalized) azimuthal distribution of ambient Noise Energy directly from the cross-correlation functions obtained through ambient Noise interferometry. The (smaller, second order) bias due to non-linearity can be reduced iteratively, for instance by using the tomographic model that results from the inversion of uncorrected data. We illustrate our method for Noise Energy estimation, phase velocity bias suppression, and ambient Noise tomography (including azimuthal anisotropy) with data from a seismic array (26 stations) in SE Tibet. We show that the phase velocity bias due to uneven Noise Energy distribution (and medium complexity) in SE Tibet has a small effect (
Dezső L. Beke - One of the best experts on this subject based on the ideXlab platform.
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Effect of the martensite twin structure on the deformation induced magnetic avalanches in Ni2MnGa single crystalline samples
Scripta Materialia, 2016Co-Authors: Lajos Daróczi, Szilvia Gyöngyösi, L.z. Tóth, Dezső L. BekeAbstract:Abstract The Noise Energy versus strain functions, obtained from bending deformation induced magnetic Noises, are different for different twin structures of Ni 2 MnGa single crystals and have two characteristically different stages: unipolar magnetic signals, reflecting the elastic strain induced rearrangement of magnetic domains, as well as bipolar signals, belonging to rearrangements of the martensite variant structure. The critical exponents of the probability density functions of Energy and amplitude were larger for samples with highly mobile twin II boundaries than for the other two samples in the bipolar regime. The Noise Energy is considerably smaller for the motion of twin II boundaries.
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Jerky magnetic Noises generated by cyclic deformation of martensite in Ni2MnGa single crystalline shape memory alloys
Applied Physics Letters, 2015Co-Authors: Lajos Daróczi, Szilvia Gyöngyösi, L.z. Tóth, S. Szabó, Dezső L. BekeAbstract:It is shown that during periodic deformation of martensitic Ni2MnGa single crystalline alloy jerky magnetic Noises are emitted. Above a threshold limit in the deformation amplitude, the Noise Energy per deformation cycle showed increasing tendency with increasing deformation. Energy and amplitude probability distributions of the Noise were characterized by power law functions. The Energy exponents were independent of the deformation amplitude in the investigated range. The decrease of the Noise Energy as well as power exponents with increasing magnetic field was interpreted by the decrease of the multiplicity of the martensite variants.
